Diagnostic method based on the analysis of the vibration and acoustic emission energy for emergency diesel generators in nuclear plants

Detection of Changes in the Opening Pressure of Marine Engine Injectors Using Vibration Methods

“…The exploitation of the marine engine fuel supply system takes place in marine conditions, which are considered the most diffi cult, and it is refl ected in the high intensity of damage [1,8]. This is due to the destructive impact and use of the engine at low and variable loads, the possibility of water in the fuel, as well as salt and seawater in the intake air, cyclical overloads, etc.…”

“…), -lack of immediate reaction of technical personnel to minor primary damage of structural elements, aff ecting the quality of the fuel system operation, -repeated engine starts, frequent changes of its load and longlasting work at low loads, -chemical corrosion caused by the aggressive infl uence of the factors contained in fuel (sulphur and vanadium), especially during long engine stoppages, -erosive eff ect of solid particles contained in the fuel, as well as cavitation erosion of fl ow channels, -thermal eff ect of the heated engine on precise dosing elements. Many scientists devote their attention to issues related to the diagnostics of diesel engine injectors [1,2,3,4,5,6,7,8,9,12,14,15,16,17]. Currently, the most eff ective way to assess the technical condition of injectors is their disassembly and testing on the dedicated test benches [14].…”

Marine diesel engine common rail injectors monitoring with vibration parameters

“…Operational problems resulting from the use of electronically controlled common rail injectors result mainly from the very high precision of their components and the degree of complexity of the injector, which is larger than in the classical injection equipment. CR injectors can be precisely controlled and tested on the test bench under laboratory conditions, whereas in "field conditions" their diagnosis is practically limited to measuring the volume of fuel flowing out of the control chamber of individual injectors or from all injectors at the same time [1,8]. It follows that the personnel operating the engine on board a navy ship have very limited possibilities to determine the technical condition of the injectors.…”

“…Despite the differences in the construction of CR system injectors and typical injectors in both cases, the main source of vibrations recorded on their hulls are phenomena associated with the lift and fall of the injector needle related to the opening and closing of the injector. The equation describing dynamics of the Common Rail injector needle according to [10] is: (1) where:…”

“…Taking into consideration the right side of the equation (1) and the construction of Common Rail injectors it can be stated that mechanical damage will result in pressure changes in the different parts of the injector nozzle. Mechanical damage to the control valve will result in a drop of pressure in the control chamber.…”